Carboxylate half esters of 1-aza-3,7-dioxabicyclo[3.3.0] oct-5-yl methyl alcohols, their preparation and use as additives for oleaginous compositions

ABSTRACT

Ester derivatives of 1-aza-3,7-dioxabicyclo [3.3.0] oct-5-yl methyl alcohols which are the reaction products of organic acid materials, preferably long chain dicarboxylic anhydrides such as octadecenyl and polyisobutenylsuccinic anhydrides and aldehyde/tris [hydroxy-methyl] aminomethane (THAM) adducts or mixtures are oleaginous compositions which feature activity in gasoline as rust inhibitors and carburetor detergents; in automatic transmission fluids as friction modifiers and rust inhibitors; and, in automotive, industrial and lubricating oils as sludge dispersants, rust-inhibitors, friction modifiers and copper alloy corrosion inhibitors, the particular use depending on the molecular weight of the ester.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to novel oil soluble esters derived from thereaction of organic acid materials such as dicarboxylic acids oranhydrides and an aldehyde/tris-(hydroxymethyl) aminomethane adduct ormixture. These novel oil soluble esters have utility as additives foroleaginous compositions and systems including gasoline, automatictransmission fluids and lubricating oils and as synthetic lubricants,per se.

2. Description of the Prior Art

Lubricant and fuel additives derived from hydrocarbon substitutessuccinic anhydride, e.g., polyisobutenylsuccinic anhydride, withcompounds containing both an amine group and a hydroxy group have beensuggested or investigated in the prior art. For example, U.S. Pat. No.3,272,746 teaches the reaction of ethanolamine and diethanolamine, aswell as various hydroxyalkyl substituted alkylene amines, such asN-(2-hydroxyethyl) ethylene diamine, N,N'-bis(2-hydroxyethyl) ethylenediamine, with alkenylsuccinic anhydride to obtain ashless dispersantsfor lube oil. U.S. Pat. No. 3,324,033 shows a hydroxy amine, such asdiethanolamine reacted with a long chain alkenyl-succinic anhydride toform a mixture of esters and amides, wherein some of the diethanolaminereacts through a hydroxy group to give an ester linkage, while anotherportion of the diethanolamine forms an amide linkage. U.S. Pat. No.3,364,001 teaches a tertiary alkanolamine reacted with analkenylsuccinic anhydride to form an ester useful as a gasolineadditive. U.S. Pat. No. 3,448,049 teaches dispersants, corrosioninhibitors and antiwear agents in lubricants and fuels by esterifyingalkenylsuccinic anhydride with a hydroxy compound made by reacting analkanolamine with an unsuaturated ester, amide or nitrile. U.S. Pat. No.3,630,904 teaches reacting a hydroxy amine, with both short and longchain discarboxylic acid. U.S. Pat. No. 3,484,374 teaches the polymericcondensation products of polycarboxylic acid or anhydride with variousalkanolamines such as aminoethyl-ethanolamine, N-methyldiethanolamine,etc. United Kindom Specification 809,001 teaches corrosion inhibitorscomprising a multiple salt complex derived from the reaction product ofhydrocarbyl substituted dicarboxylic acids and hydroxy amines (including2-amino-2-methyl-1,3-propane-diol [AMP] and tris hydroxymethylaminomethane (hereafter designated THAM) further complexed withmono- and polycarboxylic acids.

U.S. Pat. No. 3,756,743 teaches reacting polyisobutenylsuccinicanhydride with a polyol, such as pentaerythritol, followed by reactionwith THAM. U.S. Pat. No. 3,632,511 teaches reactingpolyisobutenylsuccinic anhydride with both a polyamine and a polyhydricalcohol including THAM. U.S. Pat. No. 3,679,428 teaches reactingpolyisobutenylsuccinic anhydiride with a mixture of pentaerythritol andTHAM. United Kingdom Specification 984,409 teaches ashless,amide/imide/ester type lubricant additives prepared by reacting analkenylsuccinic anhydride, with a hydroxy amine including THAM.

In British Pat. No. 564,506, the condensation product of THAM andformaldehyde, i.e. 1-aza-3,7-dioxabicyclo [3.3.0] oct-5-yl methylalcohols is said to react with fatty acids to give unstable esterproducts which are useful as drying oils.

In contrast to the above disclosures, we have found that carboxylicacids or anhydrides can be treated with an aldehyde-THAM adduct ormixture to give novel compositions useful in an unusually wide spectrumof additive applications.

SUMMARY OF THE INVENTION

It has now been discover that novel oil soluble ester derivatives of1-aza-3,7-dioxabicyclo[3.3.0] oct-5-yl methyl alcohols can be formedfrom the reaction of organic acids, preferably, dicarboxylic acids andanhydrides, with an aldehyde-(THAM) adduct or aldehyde-(THAM) mixture.For oleaginous compositions wherein the ester compositions of theinvention have been found to be highly useful as anti-rust additives,dispersants, and friction modifiers, the preferred aliphatic chain ofthe carboxylic acid has from about 6 to about 300, optimally from about12 to about 150, carbons. The aliphatic hydrocarbyl chain can bebranched and can possess unsaturation. For applications of the additivecompounds in gasoline, the carbon chain length is preferably from about12 to about 40 to 50 carbon atoms, whereas for applications inlubricating oils it is preferably from about 40 to about 300 carbonatoms, e.g. 60 to 150.

ACID MATERIALS

Numerous types of acid materials can be utilized according to thisinvention, however mono- and dicarboxylic acids which afford oil solubleesters from aldehyde/THAM adducts or mixtures are preferred. Theseinclude mono-car- boxylic acids such as palmitic, stearic,phenylstearic, isostearic, oleic, linoleic and higher molecular weightmonocarboxylic acid which can be conveniently formed from the reactionof acrylic acid with polyolefins or with chlorinated polyolefins.Especially preferred reactants are di-carboxylic acid materials,particularly aliphatic substituted succinic acid anhydrides.

Any 2-aldyl, 2-alkenyl-, 2,3-dialkyl or 2,3-cycloalkenyl substituteddicarboxylic acid material, i.e. acid, anhydride or ester e.g., succinicacid anhydride or its corresponding acid, or mixtures thereof can beused in the present invention. The alkyl or alkenyl group can bebranched or straight chain, and there is no real upper limit to thenumber of carbon atoms therein.

It is particularly preferred that the aliphatic substituent in the2-position of the succinic anhydride is a polymer of C₂ to C₅monoolefins, e.g., ethylene, propylene, butylene, isobutylene andpentene. The polymers can be homopolymers such as polyisobutylene andstyrene as well as copolymers of two or more of monoolefins such ascopolymers of ethylene and propylene, butylene and isobutylene or ofpropylene and isobutylene. Still other copolymers than can be usedinclude those in which one of the monomers is a diolefin, e.g., acopolymer of isobutylene and butadiene or a copolymer of ethylene,propylene and 1,4-hexadiene.

The polymers will have average molecular weights within the range ofabout 500 and about 100,000, or moreusually between about 800 and about20,000. Particularly useful olefin polymers have average molecularweights within the range of about 900 and about 3000 with approximatelyone double bond per polymer chain. An especially valuable startingmaterial for a highly potent dispersant additive made in accordance withthis invention is polyisobutylene having an average molecular weight inthe range of about 900 to about 2300. Molecular weights are convenientlydetermined by vapor phase osmometry; said determinations being used forall values set forth herein.

Especially useful when it is desired that the additives also possessviscosity index improving properties are 25,000 to 100,000 averagemolecular weight terpolymers of ethylene-propylene and a diene, e.g., aterpolymer of 25 to 75 weight percent propylene, 2 to 9 percent of adiene such as 1,4-hexadiene, dicyclopentadiene.

The substituted succinic anhydrides are readily available from thereaction of maleic anhydride with polyolefins or with chlorinatedpolyolefins. Interaction of polyolefins with maleic anhydride [enereactions] gives polyalkenylsuccinic anhydrides. The olefin polymer can,if desired, be first halogenated, for example, chlorinated or brominatedto about 2 to 5 wt. % chlorine, or about 4 to 8 wt. % bromine, based onthe weight of polymer, and then reacted with the maleic anhydride (seeU.S. Pat. No. 3,444,170).

Other halogenation techniques for attaching the dicarboxylic acidmaterial to a long hydrocarbon chain, involve first halogenating theunsaturated dicarboxylic acid material and then reacting with the olefinpolymer, of by blowing halogen gas, e.g. chlorine, through a mixture ofthe polyolefin and unsaturated dicarboxylic acid material, then heatingto 150° to 220° C. in order to remove HCl gas, e.g., see U.S. Pat. No.3,381,022 and 3,565,804.

In summary therefore, the dicarboxylic acid material used in theinvention includes alpha-beta unsaturated C₄ to C₁₀ dicarboxylic acid oranhydrides or esters thereof such as fumaric acid, itaconic acid, maleicacid, maleic anhydride, malic acid, maleamic acid, chloromaleic acid,dimethyl fumarate, etc. These dicarboxylic acid materials aresubstituted with a hydrocarbon chain containing at least about 2 carbonsto more than 300 carbons, preferably from about 12 to about 150depending upon the nature of composition into which the additive will beincorporated, that is, for oleaginous compositions such as gasoline, thecarbon chain length ranges from 12 to 70 carbons, for automatictransmission fluids the carbon chain length of the hydrocarbyl portionranges from 12 to 24 carbons and for the lubricating oil composition, itwould range from 12 to 300 carbon atoms.

As earlier stated, numerous acids can be reacted with aldehyde/THAMadducts or mixtures. These acids are illustrated by the following types:aromatic acids such as benzoic, phthalic, mellitic and pyromellitic;thioacids such as tridecanethionic, tridecanethiolic andtridecanethionothiolic, heterocyclic acids such as furoic and thienoicacid.

ALDEHYDE-THAM ADDUCTS

The requisite aldehyde/THAM adducts, more specifically1-aza-3,7-dioxabicyclo[3.3.0] oct-5-yl methyl alcohols (I), can bereadily prepared by condensing two moles of aldehyde with one mole ofTHAM (Equation 1) according to the procedures described by M. Senkus inthe Journal of the American Chemical Society, 67, 1515 (1945). ##STR1##Thus, a variety of aldehydes such as formaldehyde, acetaldehyde,propionaldehyde, butyraldehyde, isobutyraldehyde, 2-ethylhexanal,dodecyl aldehyde, benzaldehyde, tolualdehyde, anisaldehyde, piperonal,naphthaldehydes, phenylacetaldehyde, furfural, etc., can be condensedwith (THAM) to produce symmetrically substituted (I, R=R) aldehyde/THAMadducts.

UNSYMMETRICAL ADDUCTS

In another embodiment of the present invention, unsymmetrical adductsmay be prepared by first treating THAM with one mole of an aldehyde orketone (Equation 2) to generate an oxazolidine product (II) according toprocedures described in the literature by E. D. Bergmann, ChemicalReviews, 53, 309 (1953). ##STR2## Subsequent treatment of theoxazolidine with a mole of aldehyde affords the unsymmetrical adductIII, as depictured in Equation 3. ##STR3##

Aldehyde reactants described in the preparation of symmetricallysubstituted adducts (I) above are suitable for the reactions describedin Equations 2 and 3.

Numerous types of ketone reactants can be employed in the formation ofthe oxazolidines (Equation 2) required in the design of unsymmetricallysubstituted 1-aza-3,7-dioxabicyclo[3.3.0] oct-5-yl methyl alcohols(III). Included in the repertory of useful ketones are acetone,butanone, pentanones, methyl isobutyl ketone, pinacolone, amyl methylketone, cyclopentanone, cyclohexanone, acetophenone, etc.

Long chain aldehydes and ketones formed in the oxidation of copolymersof ethylene and propylene, butylene and isobutylene, and ethylene,propylene and 1,4-hexadiene can also be employed. The aldehyde andketone functionalized polymers will have average molecular weightswithin the range of about 500 to about 100,000.

In forming unsymmetrical adducts (III) from oxazolidine generated fromketone reactants, a particularly preferred aldehyde is formaldehydewhich, owing to its favorable steric requirements, rapidly cyclizes theoxazolidine intermediate to the desired bycyclic structure, III (R'=H).

In still another embodiment of the instant invention, it has beendiscovered that glyoxal reacts with THAM when it is placed together inequimolar concentrations to give a novel cyclic diol structure ##STR4##which is hereafter denoted as "glytham". The reaction of "glytham" withcarboxylic acid anhydrides leads to esterification of both hydroxylgroups.

REACTION CONDITIONS

The formation of the novel esters of the present invention can beeffected by reacting a mole of dicarboxylic acid anhydride with a moleof an aldehyde/THAM adduct i.e. equimolar as portrayed in Eqn. 4.##STR5## The mode of addition of reactants does not appear to affectproduct composition, and convenience will usually dictate which reagentis added to the other. Zinc salts such as zinc acetate, chloride, etc.when required, can be employed to catalyze the esterification process.In general, the reaction is effected in a reactor in the absence of orpresence of an inert diluent such as xylene and solvent oil and heatingthe mixture from about 50° C. to about 230° C. preferably 70° C. to 150°C. for about 10 minutes to 48 hours, more preferably 1 to 3 hours.Completion of reaction can be readily discerned by infrared analysis.

The disappearance of the characteristic anhydride carbonyl absorptionbands, together with the presence of strong ester and carboxylic acidcarbonyl bands indicate that complete esterification has occurred.

In some instances, the half acid ester products (IV) may be furtheresterified with simple alcohols to afford mixed diesters. Moreover,mono- and polycarboxylic acids and esters can, under certain conditions,be reacted with aldehyde/THAM adducts to give mono and polyesters usefulas combustion chamber deposit modifiers and as synthetic lubricants.

In another embodiment of the present invention, the preparation of esterproducts can sometimes be achieved by simply combining the carboxylicacid or anhydride reactant with a mixture of aldehyde and THAM in theproper molar proportions and heating the well-mixed reagents (neat or indiluent) at about 80° C. to about 220° C. for about 1-24 hours, or untilinfrared analyses of the mixture indicate that product formation iscomplete. In such instances, particularly with formaldehyde as reactant,the rate of aldehyde/THAM adduct formation apparently is quite rapid inthe presence of the carboxylic acid reactant which at some point,undergoes interaction with the aldehyde/THAM adduct to generate thedesired ester.

In a preferred embodiment of the present invention, the symmetricaladduct can be formed in situ, by heating a mixture of 2 moles ofaldehyde and a mole of THAM at about 80° C. to about 210° C. for about 1to about 4 hours. Quite often infrared analysis can be used to discerncomplete reaction by the disappearance of the aldehyde carbonylabsorption bond. In instances where unsymmetrical adducts are desired, amole of aldehyde or ketone is heated with a mole of THAM at about 80° C.to about 210° C. for about 1 to about 24 hours, or until periodicinfrared analyses of the reaction mixture show the absence of a carbonylabsorption band. Thereafter, a mole equivalent of aldehyde, preferablyformaldehyde is added to the intermediary oxazolidine and the mixture isheated at about 80° C. to about 210° C. for approximately 1 to about 4hours. The insitu formed adduct can thereafter be reacted with acarboxylic acid or anhydride by adding, for example, a mole ofalkenylsuccinic anhydride to the adduct and heating the well-stirredreaction mixture at about 80° C. to about 200° C. for approximately 15minutes to about 4 hours, or until the infrared spectrum of the reactionmixture reveals the absence of the characteristic anhydride carbonylabsorption bands.

The following preparations and examples are included herein as furtherdescription and illustrative of the present invention.

PREPARATION OF ALDEHYDE-THAM ADDUCTS EXAMPLE 1

0.1 mole (12.1 g) of THAM was dissolved in an equal weight of water. Tothe resulting solution in a 250 ml. Erlenmeyer flask equipped withmagnetic stirrer was added 0.2 mole (6.0 g) of paraformaldehyde. Thestirred mixture was heated to 70° C. to effect dissolution of theparaformaldehyde and continued for 15 minutes at 70° C. to produce the1-aza-3,7-dioxabicyclo[3.3.0] oct-5-yl methyl alcohol (hereinaftercalled DOBO) in quantitative yields. The product after evaporation ofwater and recrystallization from benzene melted at 60-61° C. andanalyzed for 49.12% carbon, 7.52% hydrogen and 9.59% nitrogen.

EXAMPLE 2

1.0 mole (121 g) of THAM was added in one portion to 145 grams of 40%glyoxal in water. As the THAM dissolved the temperature rose from about25° C. to 35° C. The solution was then stirred at 50° C. for 10 minutesand product began to separate from solution. The mixture was stirred at50° C. overnight. Filtration afforded a white solid product whichweighed 85 g. after drying. Recrystallization from boiling water gave awhite solid which melted at 291-292° C. The infrared spectrum of theproduct as a Nujol mull featured prominent absorption bands at 3.05,9.38, 9.63, 10.45 and 13.07 microns. The analysis base on C₁₂ H₁₈ N₂ O₆was: Calculated C,50.34; H, 6.34; N, 9.78, and found C, 50.22; H, 6.32;N, 9.66. The product of this example is hereinafter called "glytham".

ESTERIFICATION OF ALDEHYDE-THAM ADDUCTS EXAMPLE 3

The bis-acetate ester of "glytham" was formed by refluxing 1 mole ofacetic anhydride with 1 mole of glytham using a catalytic amount of zincchloride salt. The bis-acetate ester melted at 196-197° C. The productester's infrared spectrum featured strong absorption bands at 5.77,7.90, 9.27, 9.67 and 13.70 microns. The NMR spectrum of the diester inCDCl.sub. 3 showed four singlets positioned at 5.21, 5.82, 6.14, and7.94 tau in the expected intensity ratio. The molecular weight of thebis-acetate ester measured by vapor phase osmometry was 380.

EXAMPLE 4 1-AZA-3,7-DIOXABICYCLO[3.3.0] OCT-5-YL METHYL STEARATE

A 0.1 mole (28.5 g) of stearic acid, 0.1 mole of (DOBO) and 100 ml ofxylene were charged into a 500 ml 4-neck round bottom flask equippedwith thermometer, stirrer and a Dean Stark moisture trap mounted with areflux condenser. The mixture was refluxed for about 3 hours. Infraredanalyses revealed that esterification was essentially complete, and thesolvent was then removed by rotoevaporation. The product (41.2 g) wassoluble in heptane and xylene.

EXAMPLE 5 HALF ACID ESTER OF 1-DIOXABICYCLO[3.3.0] OCT-5-YL METHYLOCTADECENYLSUCCINATE

0.5 mole of octadecenylsuccinic anhydride was added to a 1 liter roundbottom flask and heated to 140° C. for an hour to convert any partiallyhydrolyzed reactant to the anhydride form. After cooling thenitrogen-blanketed reactor to 100° C., 0.5 mole of DOBO was added in oneportion. The alcohol reagent readily dissolved and the clear solutionwas heated to 174° C. for about 2 hours. Infrared analysis showed thatesterification was complete at this point. The infrared spectrum of thetan product featured prominent absorption bands at 5.75, 5,85, 8.65,9.10, 10.3 and 10.7 microns.

Analysis based on C₂₈ H₅₀ NO₆ :

Calculated: C, 67.70; H, 10.15; N, 2.82,

Found: C, 66.57; H, 9.95; N, 2.60,

The product, recrystallized from hexane, melted at 58-62° C.

EXAMPLE 6 HALF ACID ESTER OF 1-AZA-3,7-DIOXABICYCLO [3.3.0]OCT-5-YLMETHYL POLYISOBUTYLENESUCCINATE

0.2 mole (267 g) of polyisobutenylsuccinic anhydride of MW 980 with aSap. No. of 84 was charged into a 1 liter flask and heated to 180° C.The anhydride reactant is heated at 180° C. under high vacuum for 2hours to remove any light ends. About 2.8 g of volatiles were collectedin a dry ice-cooled receiver. The stirred reactant is then cooled to120° C., and 0.2 mole (29.0 g) of DOBO plus 1 gram of zinc acetatecatalyst are added. The stirred reaction mixture is then heated at 210°C. for several hours until infrared analysis shows completeesterification. An equal weight of neutral oil (S-150N) is added to theproduct at about 120° C. The diluted product analyzed for 0.42% nitrogenand featured an infrared spectrum with a dominant absorption band at5.75 microns.

EXAMPLE 7

0.1 mole (133.5 g) of polyisobutenylsuccinic anhydride of MW 980 with aSap. No. of ca 84 and 0.1 mole (28.6 g) of glytham were charged into a500 ml 4-necked round bottom flask. The reaction mixture was blanketedwith nitrogen and heated in an oil bath to about 190° C. for 16 hours.The cooled mixture was diluted with 250 ml. of heptane, and filtered.Approximately one-half (16 g) of the glytham was recovered. The filtratewas rotoevaporated to remove solvent and the residue (138 g) was dilutedwith an equal weight of oil (S-150N). The diluted product featured aninfrared spectrum with a strong absorption band at 5.73 microns andanalyzed for 0.7% nitrogen.

EXAMPLE 8 HALF ACID ESTER OF1-AZA-3,7-DIOXA-2,8-DI-N-PROPYL-BICYCLO[3.3.0] OCT-5-YL METHYLOCTADECENYL-SUCCINATE

0.27 mole (94.5 g) of normal octadecenylsuccinic anhydride was added toa 500 ml flask and heated for an hour at 140° C. to convert anypartially hydrolyzed reactant to the anhydride form. The reaction wascooled to 70° C. and 0.3 mole (68.7 g) of1-aza-3,7-dioxa-2,8-di-n-propyl bicyclo [3.3.0] oct-5-yl methyl alcoholwas added to the flask and heating was maintained for 1 hour at 98°-104°C. The I.R. spectrum of the product showed disappearance of anhydridebands and the appearance of 2 bands at 5.75 and 5.85 microns.

EXAMPLE 9 HALF ACID ESTER OF 1-AZA-3,7-DIOXA-2,8-DIPHENYL BICYCLO[3.3.0]OCT-5-YL METHYL OCTADECENYL SUCCINATE

0.27 mole (94.5 g) of n-octadecenylsuccinic anhydride was added to a 500ml. flask and heated for an hour at 140° C. The reaction was cooled to70° C. and 0.30 moles (89.1 g) of1-aza-3,7-dioxa-2,8-diphenyl-bicyclo[3.3.0] oct-5-yl methyl alcohol wasadded to the flask and heating continued for 1 hour at 107°-114° C. TheI.R. spectrum of the product showed the appearance of 2 bands at 5.75and 5.85 microns.

EXAMPLE 10 HALF ACID ESTER OF 1-AZA-3,7-DIOXABICYCLO[3.3.0] OCT-5-YLMETHYL TETRAPROPENYLSUCCINATE

0.8 mole (212.8 g) of tetrapropenylsuccinic anhydride was combined with0.8 mole (116 g) of DOBO in a 1 liter flask and heated to 138° C. for 2hours. The product analyzed for 3.2% nitrogen. The calculated value is3.4%. The I.R. spectrum of the product shows a broad band at about 5.8microns.

EXAMPLE 11 HALF ACID ESTER OF1-AZA-3,7-DIOXA-2,8-DI-N-PROPYL-BICYCLO[3.3.0] OCT-5-YL METHYLTETRAPROPENYL SUCCINATE

0.3 mole (79.8 g) of tetrapropenylsuccinic anhydride was reacted with0.3 mole (68.7 g) of 1-aza-3,7-dioxa2,8-di-n-propyl-bicyclo[3.3.0]oct-5-yl methyl alcohol in a 500 ml flask at 100° C. for 2 hours. Theweight percent nitrogen in the product was 2.81%. The calculated valuewas 2.83%. The IR spectrum of the product showed 2 bands, at 5.75 and5.85 microns.

EXAMPLE 12 HALF ACID ESTER OF 1-AZA-3,7-DIOXA-2,8-DIPHENYLBICYCLO[3.3.0] OCT-5-YL METHYL TETRAPROPENYL-SUCCINATE

0.2 mole (53.2 g) of tetrapropenylsuccinic anhydride was combined with0.2 mole (59.4 g) of 1-aza-3,7-dioxa- 2,8-diphenyl-bicyclo[3.3.0]oct-5-yl methyl alcohol in a 500 ml flask and heated to 100°-106° C. for2 hours. The I.R. spectrum of the product showed 2 bands at 5.75 and5.85 microns.

EXAMPLE 13 HALF ACID ESTER OF 1-AZA-3,7-DIOXABICYCLO [3.3.0] OCT-5-YLMETHYL n-DODECENYLSUCCINATE

0.25 mols (66.8 g) of n-dodecenylsuccinic anhydride was heated at160°-180° C. for 3 hours with a nitrogen sparge to dehydrate any acidpresent. It was then cooled to 90° C. and 0.25 moles (38 g) of DOBO inoctane was added and the mixture heated 1 hour at 90° C. -110° C. Theproduct showed no anhydride bands in the I.R. spectrum at 5.4 and 5.6microns and contained 3.7 wt. % nitrogen.

The following example teaches the formation of products via the reactionof an unsymmetrical adduct formed by successive additions of molaramounts of ketone and aldehyde to THAM followed by esterification of theadduct with succinic anhydride.

EXAMPLE 14

A quarter mole of THAM was combined with a half mole of cyclohexanoneand the mixture heated at reflux until a clear solution was obtained.The solid product which formed on cooling the solution, wasrecrystallized from boiling toluene. The dried product, melted at119°-120° C. and was found to be desired cyclohexanone/THAM adduct,i.e., 2-spiro-(cyclohexyl)-4,4-bis(hydroxymethyl)-oxazolidine. Thirtygrams (0.149 mole) of the cyclohexanone/THAM adduct and 5 g (0.166 mole)of paraformaldehyde were added to 150 ml of toluene and the mixture wasrefluxed in a reactor equipped with a Dean-Stark moisture trap. After 2hours, approximately 3.1 mole of water were collected and reaction wasterminated. Removal of solvent and low ends from the reaction mixture byevaporation afforded 32.1 g of crude product which was homogeneous bygas chromatography. Vacuum distillation gave a colorless viscous liquidwhich boiled at 159°-160° C. (1.0 mm) and featured infrared and nmrspectra consistent with the unsymmetrical adduct,1-aza-3,7-dioxa-2-spiro-(cyclohexyl)-5-hydroxymethylbicyclo[ 3.3.0]octane.

Treatment of 0.1 mole of the unsymmetrical adduct with 0.1 mole ofsuccinic anhydride gave the expected half acid-ester product in highyield.

The above examples teach the preparation of the products of the presentinvention via the reaction of a carboxylic acid or anhydride, preferablythe latter, with a discrete aldehyde/THAM adduct, which is firstisolated, purified and characterized (if required), and then employed ina second step involving the esterification of a suitable carboxylic acidor anhydride reagent by the adduct alcohol.

We have also discovered that in certain instances, other syntheticoptions were also effective and oftimes more convenient in preparing theproducts of the present invention. One approach involves the addition ofa carboxylic acid or anhydride to an aldehyde/THAM adduct which isformed in situ, by simple heating the aldehyde and THAM reagentstogether as illustrated in Example 15.

EXAMPLE 15 HALF ACID ESTER OF 1-AZA-3,7-DIOXABICYCLO[3.3.0] OCT-5-YLMETHYL n-OCTENYLSUCCINAMATE

In a typical reaction, 2 moles (60 g) of paraformaldehyde is added to 1mole (121 g) of (THAM) and gradually heated with stirring to about 110°C. Heating is continued at 110°-120° C. until a clear solution wasobtained. After stirring for 15 minutes, a mole of n-octenylsuccinicanhydride is added to the reactor which is maintained at about 120° C.After the addition of n-octenylsuccinic anhydride is completed, theclear solution is stirred at 120°-130° C. until infrared analysis showsthe absence of anhydride bands, e.g. for from about 15to 30minutes.Reaction times of 0.25-1hours, e.g. 15-30 minutes, at 130-140° C. aresufficient to produce the desired ester derivative.

Finally, a second approach which is also operative in certain cases,simply involves the addition of a carboxylic acid or anhydride to thealdehyde and THAM reagents (in the required molar proportions) andheating the resulting mixture until product formation is complete asdiscerned by infrared analysis. Example 16 describes briefly theexperimental details of this approach.

EXAMPLE 16

A mixture comprising a tenth mole of paraformaldehyde, 0.05 mole of THAMand 0.05 mole of n-octenylsuccinic anhydride is gradually heated, withstirring, to about 160°-170° C. for about an hour. The infrared spectrumof the reaction product was virtually identical to that recorded for theproduct obtained in Example 15.

USE OF THE ESTER ADDITIVE IN OLEAGINOUS COMPOSITIONS

The oil-soluble ester reaction products of this invention can beincorporated into a wide variety of oleaginous compositions. They can beused in lubricating oil compositions, such as automotive crankcaselubricating oils, automatic transmission fluids, etc., in concentrationsgenerally within the range of about 0.01 to 20 weight percent, e.g. 0.1to 10 weight percent, preferably .3 to 3.0 weight percent, of the totalcomposition. The lubricants to which the ester products can be addedinclude not only hydrocarbon oils from petroleum, but also includesynthetic lubricating oils such as polyethylene oils; alkyl esters ofdicarboxylic acid; complex esters of dicarboxylic acid, polyglycol andalcohol; alkyl esters of carbonic or phosphoric acids; polysilicones;fluorohydrocarbon oils; mixtures of mineral lubricating oil andsynthetic oils in any proportion, etc.

When the products of this invention are used as multifunctionaladditives having detergents, antirust properties in petroleum fuels suchas gasoline, kerosene, diesel fuels, No. 2 fuel oil and other middledistillates, a concentration of the additive in the fuel in the range of0.001 to 0.5 weight percent, based on the weight of the totalcomposition, will usually be employed.

When used as an antifoulant in oil streams in refinery operations toprevent fouling of process equipment such as heat exchangers or inturbine oils, about 0.001 to 2 wt. % will generally be used.

The ester additives may be conveniently dispensed as an additiveconcentrate of from 2 wt. % to 100 wt. % with the balance conventionallya mineral lubricating oil e.g. up to 98 weight percent, with or withoutother additives being present.

In the above compositions or concentrates, other conventional additivesmay also be present including dyes, pour point depressants, antiwearagents such as P₂ S₅ -treated terpene or zinc dialkyl dithiophosphatesof 3 to 8 carbon atoms in each alkyl group, antioxidants such asN-phenyl-α naphthylamine, tert-octylphenol sulfide, 4,4'- methylenebis(2,6-di-tert-butyl phenol), viscosity index improvers such asethylene-propylene copolymers, polymethacrylates, polisobutylene, alkylfumerate-vinyl acetate copolymers and the like, de-emulsifiers such aspolysiloxanes, ethoxylated polymers and the like. The esters of theinvention can also be used as synthetic lubricants.

The invention will be further understood by reference to the followinguse examples, which include preferred embodiments of the invention.

GASOLINE ADDITIVES

The products of Examples 4, 5, 6 and 9 were tested for theireffectiveness as gasoline antirust agents. Each product was firstdissolved in xylene and the solutions added to the gasoline toincorporate the additive at a treat rate of 12 pounds of ester additiveper thousand barrels of gasoline. The gasoline so treated was thentested for rust according to ASTM D-665M rust test. In brief, this testis carried out by observing the amount of rust that forms on a steelspindle after rotating for an hour in a water-gasoline mixture. In eachcase, the ester treated gasoline gave no rust indicating that eachproduct was very effective as an antirust additive since the untreatedgasoline will form rust over the entire surface of the spindle. Thechemical structure of the ester products of the invention and mostparticularly, the nature of the alkyl or alkylene hydrocarbyl chain ofthe carboxylic acids determines in part the useful concentration rangeof the additive to be incorporated into the gasoline. The product ofExample 6, for example, broadly is useful at treat rates of 3 pounds toabout 35 pounds per thousand barrels of active ingredient and in apreferred range is from about 5 to about 25 pounds and optimally shouldbe about 6 to about 121/2 pounds per thousand barrels. This treat rangeis also suitable for the product of Example 5, whereas for the productof Example 4 a higher treat rate is desired as for example the broadrange should be around 3 to about 35 pounds per thousand barrels, butthe preferred range is from about 12 to about 25 pounds per thousandbarrels and optimally should be from about 15 to about 20 pounds perthousand barrels.

Another application of these additives which has been earlier referencedis their addition to gasoline as a carburetor detergent. Particularlyuseful as such a detergent is the product of Example 5 which for optimalcarburetor detergency is incorporated into the gasoline at a treat rateof about 6 pounds to about 121/2 pounds per thousand barrels with about10 pounds per thousand barrels being the preferred level. If theadditive is also desired to impart anti-stall characteristics to theautomobile and to the gasoline then the treat rate which is used forcarburetor detergency should be about double in order to provide bothcharacteristics, that is a treat rate of the product, for example,Example 6 of about 121/2 pounds to about 25 pounds per thousand barrels.

The efficiency of the additive of the invention as carburetordetergencies were made by evaluating the effect of the additive of theinvention in comparison with a commercial product consisting of thereaction product of polyisobutenyl succinic anhydride and polyamine,i.e. with the product of Example 6. The treat rate of the gasoline wasat a rate of 25 pounds per thousand barrels of the additive of Example 6with a treat rate of 45 pounds per thousand barrels of the reactionproduct of polyisobutenyl/succinic anhydride and polyamine. The vehicleswhich were subjected to test were two 1974 taxis with the product ofExample 6 and a 1973 taxi with the commercial additive. The vehicleswere Ford, 302 CID, V-8's equipped with emission control hardware. Theoil used was SAE 30 SE level. The driving schedule was for a distance of8000 miles of which 10% was freeway driving, 30% was idle conditions and60% was stop and go with a mean velocity of about 30 miles per hour. Theresults of the test shown in Table I were as follows:

                  TABLE I                                                         ______________________________________                                                        Carburetor rating (10 = clean)                                Additive          Initial     Final                                           ______________________________________                                        Prod. Example 6   7.2         9.9                                                               8.4         9.7                                             Commercial        7.5         9.9                                             ______________________________________                                    

The results above indicate that the gasoline additive of the inventionpossesses carburetor detergency comparable to the commercially availableadditive.

AUTOMATIC TRANSMISSION FLUID ADDITIVE

As earlier indicated, the additives of the invention also haveapplication as friction modifiers. In particular, the product of Example5 is a useful friction modifier for incorporation into automatictransmission fluids, (ATF) to reduce the component interactions, withoutdeteriorating the frictional properties of the ATF. The ATF lubricantscontain many component additives which are typically blended into thelubricating mineral oil at the following range of treating levels.

    ______________________________________                                        Components         Concentration range, vol. %                                ______________________________________                                        V.I. improver         1-15                                                    Corrosion inhibitor   0.01-1                                                  Oxidation inhibitor   0.01-1                                                  Dispersant            0.5-10                                                  Pour Point depressant 0.01-1                                                  De-emulsifier         0.001-0.1                                               Anti-foaming agent    0.001-0.1                                               Anti-wear agent       0.001-1                                                 Seal swellant         0.1-5                                                   Friction modifier     0.01-1                                                  Mineral oil           Balance                                                 ______________________________________                                    

As indicated above, the friction modifier is optimally the reactionproduct of Example 5. The treat rate is obvious from the above typicalformulations which has been blended for the ATF lubricant. A furtheradvantage has developed from using the additives of the invention asfriction modifiers for ATF lubricants, i.e. a reduction in the coppercorrosiveness of commercial ATF lubricants, after substitution of thecommercial friction modifier with an additive of the invention. Thefollowing data is illustrative of the copper corrosion inhibitionimprovement of ATF lubricants.

Two commercial ATF lubricants I and II were examined in the followingcopper corrosion test in both modified and unmodified form. The coppercorrosion test is carried out as follows: A copper specimen 3 × 1/2 ×1/16 is polished until clean and uniform, washed in hexane, dried andweighed to the tenth of a milligram. 50 cc of the test fluid is placedin a test tube into which the copper bar is immersed, and the test tubethereafter corked with a cork with two 1/8 holes in it. The tube isplaced in a 300° C. aluminum block for 72 hours. At the end of the time,the specimen is removed, washed in hexane, rubbed vigorously with papertowel to remove any loose deposits, rewashed and reweighed.Alternatively, the sample may be blown with dry air at 25 cc/min. duringthe test.

                  TABLE II                                                        ______________________________________                                        Copper Corrosion Tests, mg. lost in 3 days                                    ATF          ATF I     ATF I      ATF II                                      ______________________________________                                        Lubricant    Air blown No air blown                                                                             No air blown                                ______________________________________                                        Unmodified   17.9      21.7       16.7                                        Modified by removal                                                           0.2 wt. % friction                                                            modifier     18.9      21.7       13.7                                        Modified by removal                                                           0.2 wt. % friction                                                            modifier and addition                                                         of 0.2 wt. % of Prod.                                                         Example 5.    7.2       6.5        0.7                                        ______________________________________                                    

SLUDGE INHIBITION BENCH (SIB) TEST

A number of the additives of this invention were subjected to a SludgeInhibition Bench (SIB) Test which has been found, after a large numberof evaluations, to be an excellent test for assessing the dispersingpower of lubricating oil dispersant additives.

The medium chosen for the Sludge Inhibition Bench Test was a usedcrankcase mineral lubricating oil composition having an originalviscosity of about 325 SUS at 100° F. that had been used in a taxicabthat was driven generally for short trips only, thereby causing abuildup of a high concentration of sludge precursors. The oil that wasused contained only a refined base mineral lubricating oil, a viscosityindex improver, a pour point depressant and zinc dialkyldithiophosphateantiwear additive. The oil contained no sludge dispersant. A quantity ofsuch used oil was acquired by draining and refilling the taxicabcrankcase at 1000-2000 mile intervals.

The Sludge Inhibition Bench Test is conducted in the following manner.The aforesaid used crankcase oil, which is milky brown in color, isfreed of sludge by centrifuging for 1 hour at about 39,000 gravities(gs.). The resulting clear bright red supernatant oil is then decantedfrom the insoluble sludge particles thereby separated out. However, thesupernatant oil still contains oil-soluble sludge precursors which onheating under the conditions employed by this test will tend to formadditional oil-insoluble deposits of sludge. The sludge inhibitingproperties of the additives being tested are determined by adding toportions of the supernatant used oil, a small amount, such as 0.5, 1 or2 weight percent, on an active ingredient basis, of the particularadditive being tested. Ten grams of each blend being tested is placed ina stainless steel centrifuge tube and is heated at 280° F. for 16 hoursin the presence of air. Following the heating, the tube containing theoil being tested is cooled and then centrifuged for 30 minutes at about39,000 gs. Any deposits of new sludge that form in this step areseparated from the oil by decanting the supernatant oil and thencarefully washing the sludge deposits with 25 ml. of pentane to removeall remaining oil from the sludge. Then the weight of the new solidsludge that has been formed in the test, in milligrams, is determined bydrying the residue and weighing it. The results are reported asmilligrams of sludge per 10 grams of oil, thus measuring differences assmall as 1 part per 10,000. The less new sludge formed the moreeffective is the additive as a sludge dispersant. In other words, if theadditive is effective, it will hold at least a portion of the new sludgethat forms on heating and oxidation, stably suspended in the oil so itdoes not precipitate down during the centrifuging.

Using the above-described test, the dispersant action of ester additivesof the present invention was compared with the dispersing power of acommercial dispersant referred to as PIBSA/TEPA. The PIBSA/TEPA wasprepared by reaction of 1 mole of tetraethylene pentamine with 2.8 molesof polyisobutenylsuccinic anhydride obtained from polyisobutylene ofabout 1000 number average molecular weight. The PIBSA/TEPA dispersantwas used in the form of an additive concentrate containing about 50weight percent PIBSA/TEPA in 50 wt. % mineral lubricating oil. ThisPIBSA/TEPA additive concentrate analyzed about 1.14% nitrogen,indicating that the active ingredient, i.e., PIBSA/TEPA per se,contained about 2.28% nitrogen. Sufficient quantities of all theadditive concentrates tested below were used in making the test blendsto furnish the 0.5 and 1.0 weight percent of actual additive. The testresults are given in Table III.

                  TABLE III                                                       ______________________________________                                        SLUDGE DISPERSANCY TEST RESULTS                                               Milligrams of Sludge In a 10 gram Sample                                      Additive of                                                                   Example     1.0 wt. %     0.5 wt. %                                           ______________________________________                                        6           0             4.82                                                PIBSA/TEPA  0             1.87                                                ______________________________________                                    

The oil without sludge dispersants gave 10 mg. sludge/10 g. of oil as aresult of the SIB test. The additive of the invention possessesdispersant activity at concentrations of both 0.5 and 1.0 wt. %.

WARBURG TEST FOR RUST INHIBITION

The Warburg apparatus consists of a temperture controlled flaskconnected to a capillary manometer with a manometer liquid connected toa large reservoir. The test apparatus has been described by Hornerentitled "Uber die Wirkungsweise von Korrosioninhibitoren" in"Werkstoffe Und Korrosion". 23, pp. 466-474 (1972) as a measure of theantirust effectiveness of a number of organic compounds in lubricants.In carrying out the test, 3 grams of iron filings are dispersed in a 10gram sample of the lubricant to be evaluated for rust inhibitioneffectiveness. The test sample is heated for about 20 minutes at 50° C.Thereafter 0.75 ml. of 2N HCl is added to the sample. The sample is heldat 50° C. with stirring; the oxygen intake is measured after 150minutes. The additives of the invention exhibited at a concentration of1.0 wt. % in Solvent 150 Neutral Oil the following rust inhibitionvalues.

    ______________________________________                                        Additive        % Inhibition                                                  ______________________________________                                        Example 5       82                                                            Example 10      68                                                            None             0                                                            ______________________________________                                    

Clearly, the additives of the invention exhibit excellent rustinhibition activity in lubricating oils.

The invention in its broader aspect is not limited to the specificdetails shown and described and departures may be made from such detailswithout departing from the principles of the invention and withoutsacrificing its chief advantages.

What is claimed is:
 1. A lubricating oil composition comprising a majoramount of lubricating oil and in the range of about 0.01 to 20 wt. % ofan oil soluble ester which is the half ester reaction product of: (a)about 1 molar proportion of a hydrocarbyl substituted C₄ to C₁₀dicarboxylic acid or anhydride having about 6 to about 300 carbon atomsper hydrocarbyl group partly esterified with the reaction product of (b)either about 1 or 2 molar proportions of an aldehyde, or one molarproportion of ketone and one molar proportion of aldehyde, reacted withabout 1 molar proportion of tris-(hydroxymethyl) aminomethane; said halfester reaction product having a 1-aza-3,7-dioxabicyclo[3,3,0] octylring.
 2. A composition according to claim 1, wherein said hydrocarbylsubstituted acid or anhydride is alkenyl succinic anhydride.
 3. Acomposition according to claim 2, wherein said alkenyl group is apolymer of a C₂ to C₅ monoolefin.
 4. A composition according to claim 1,wherein said hydrocarbyl substituted acid or anhydride is polyisobutenylsuccinic anhydride with about 40 to 300 carbon atoms in saidpolyisobutenyl group.
 5. A composition according to claim 1, whereinsaid hydrocarbyl group contains about 12 to 24 carbon atoms.
 6. Acomposition according to claim 5, wherein said hydrocarbyl substitutedacid or anhydride is octadecenyl succinic anhydride.
 7. A compositionaccording to claim 5, wherein said hydrocarbyl substituted acid oranhydride is tetrapropenyl succinic anhydride.
 8. A compositionaccording to claim 1, wherein said aldehyde is selected from the groupconsisting of formaldehyde, glyoxal, acetaldehyde, propionaldehyde,butyraldehyde, isobutyraldehyde, 2-ethylhexanol, dodecyl aldehyde,benzaldehyde, tolualdehyde, anisaldehyde, piperonal, naphthaldehyde,phenylacetaldehyde and furfural.
 9. A composition according to claim 8,wherein said aldehyde is formaldehyde.
 10. A composition according toclaim 8, wherein said aldehyde is glyoxal.
 11. A composition accordingto claim 8, wherein said tris-(hydroxymethyl) aminomethane is reactedwith one molar proportion of said ketone and then with one molarproportion of said aldehyde, and wherein said ketone is selected fromthe group consisting at acetone, butanone, pentanone, methyl isobutylketone, pinacolone, amyl methyl ketone, cyclopentanone, cyclohexanoneand acetophenone.
 12. A composition according to claim 1, wherein theamount of said half ester reaction product is about 0.01 to 5 wt. %, andsaid half ester is the half ester reaction product of octadecenylsuccinic anhydride and the reaction product of two molar proportions offormaldehyde with one molar proportion of tris-(hydroxymethyl)aminomethane.